﻿using B.WMS.StandardReturn;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;

namespace B.WMS.AutoCode
{
    public static class AutoCode
    {
        /// <summary>
        /// 编码生成器
        /// </summary>
        /// <param name="codeType">自己的业务的名称缩写</param>
        /// <returns></returns>
        /// <exception cref="NotImplementedException"></exception>
        public static async Task<ApiResult<string>> GetCode(string codeType)
        {
            var networkTimeResult = await GetNetworkTimeAsync();
            var code = $"HZ{codeType}" + networkTimeResult.ToString("yyyyMMddHHmmss");
            //获取当前网络时间
            Console.WriteLine(code);
            return new ApiResult<string>
            {
                Code = ApiCode.Success,
                ResultData = code,
                Message = "获取成功"
            };

        }
        /// <summary>
        /// 获取网络时间
        /// </summary>
        /// <returns></returns>
        public static async Task<DateTime> GetNetworkTimeAsync()
        {
            try
            {
                //default Windows time server
                //用域名获取时候用这里
                //string ntpServer = "time.windows.com";

                // NTP message size - 16 bytes of the digest (RFC 2030)
                var ntpData = new byte[48];
                //Setting the Leap Indicator, Version Number and Mode values
                ntpData[0] = 0x1B; //LI = 0 (no warning), VN = 3 (IPv4 only), Mode = 3 (Client Mode) {52.231.114.183
                                   //用域名获取时候用这里
                                   //var addresses = Dns.GetHostEntry(ntpServer).AddressList;
                IPAddress[] IPAddressList = new IPAddress[1];
                //配置时间服务器IP
                IPAddress address = new IPAddress(new byte[] { 192, 168, 1, 1 });  // NTP IP 地址
                IPAddressList[0] = address;
                //The UDP port number assigned to NTP is 123
                var ipEndPoint = new IPEndPoint(IPAddressList[0], Convert.ToInt32(123));
                //NTP uses UDP
                var socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
                socket.Connect(ipEndPoint);
                //Stops code hang if NTP is blocked
                socket.ReceiveTimeout = 1000;

                socket.Send(ntpData);
                socket.Receive(ntpData);
                socket.Close();
                //Offset to get to the "Transmit Timestamp" field (time at which the reply
                //departed the server for the client, in 64-bit timestamp format."
                const byte serverReplyTime = 40;

                //Get the seconds part
                ulong intPart = BitConverter.ToUInt32(ntpData, serverReplyTime);
                //Get the seconds fraction
                ulong fractPart = BitConverter.ToUInt32(ntpData, serverReplyTime + 4);

                //Convert From big-endian to little-endian
                intPart = SwapEndianness(intPart);
                fractPart = SwapEndianness(fractPart);
                var milliseconds = (intPart * 1000) + ((fractPart * 1000) / 0x100000000L);

                //**UTC** time
                var networkDateTime = (new DateTime(1900, 1, 1, 0, 0, 0, DateTimeKind.Utc)).AddMilliseconds((long)milliseconds);
                return networkDateTime.ToLocalTime();
            }
            catch (Exception ex)
            {
                return DateTime.Now;
            }
        }
        /// <summary>
        /// 强制按大端解析
        /// </summary>
        /// <param name="x"></param>
        /// <returns></returns>
        static uint SwapEndianness(ulong x)
        {
            return (uint)(((x & 0x000000ff) << 24) +
            ((x & 0x0000ff00) << 8) +
            ((x & 0x00ff0000) >> 8) +
            ((x & 0xff000000) >> 24));
        }
    }
}
